Inflatable insulating material

ABSTRACT

Disclosed herein is a thermal insulating material formed of sheets of non-porous flexible material hermetically sealed together to define an inflatable volume divided into a twodimensional array of compartments joined by gas communication passages. The boundaries between the compartments of the array define a plurality of intersecting lines along which the array can be easily flexed and a valve is provided for inflation of the compartmented volume.

United States Patent 1191 Nov. 13, 1973 Leon [ INFLATABLE INSULATINGMATERIAL [76] lnvent Gonzalo S. Leon, 25 Plympton Rd.,

Sudbury, Mass. 01776 [22] Filed: July 17, 1972 21 Appl. No; 272,303

[52] US. Cl. 2/2, 161/122 [51] Int. Cl A4ld 13/00 [58] Field of Search2/2, 272; 36/29, 36/44; 161/407, 121, 122; 123

[56] References Cited UNITED STATES PATENTS v 3,008,214 11/1961 Fosteret a1. 2/2 UX 876,237 l/1908 Ridlon 2/2 2,028,060 1/1936 Gilbert t. 2/2UX 2,080,469 5/1937 Gilbert 36/29 3,219,514 11/1965 Struycken 2/272 X3,577,305 5/1971 Hines et a1 2/272 X FOREIGN PATENTS OR APPLICATIONS1,317,027 12/1962 France ..2/2 1,205,021 1/1960 France ..2/2

Primary ExaminerAlfred R. Guest Attorney-John E. Toupal [57] ABSTRACTDisclosed herein is a thermal insulating material formed of sheets ofnon-porous flexible material hermetically sealed together to define aninflatable volume divided into a two-dimensional array of compartmentsjoined by gas communication passages. The boundaries between thecompartments of the array define a plurality of intersecting lines alongwhich the array can be easily flexed and a valve is provided forinflation of the compartmented volume.

22 Claims, 7 Drawing Figures This invention relates generally to thermalinsulating materials and, more particularly, to highly flexible andconformable materials having insulation properties that can be easilyvaried to compensate for changes in ambient conditions.

Most insulating materials depend on the low thermal conductivity of airto provide their low overall conductance of heat. This is true ofprotective clothing and of building or industrial insulating materialswhich contain air spaces in their structure. In most of these, the airspaces are small enough to minimize heat transfer by convection since,under ordinary conditions, convection will begin to affect theconductance through still air when the gap exceeds five-eighths inch.But because the overall conductance of these materials depends on theheat conducted through the material as well as through the still air, itis generally desirable to minimize the former by using low conductivitymaterials when possible, by using as little material as possible whilemaintaining structural integrity; and by minimizing the number orlengthening the paths through which the heat can travel. Finally, sinceheat is also transferred by radiation across the air spaces,opacification, reflective surfacing, or radiation barriers can also beincorporated into the insulating materials.

However, in these materials the overall conductance cannot be changed atwill. This is a property that can be particularly useful, for example,in protective clothing, such as jackets or vests, or in blankets andsleeping bags wherein a single article may serve comfortably over arange of ambient temperature. Inflatable structures that have beenproposed previously to provide variable insulation consist of tubularcompartments similar in pattern to those used in air mattresses. Thesestructures have two principal limitations. First, as their thickness isincreased by inflation, their lateral dimension shrinks as much as 30percent, thus making it difficult to have the garmet fit when inflatedas well as when deflated. Secondly, the inflated material in thesestructures becomes relatively rigid and does not flex easily or conformin shape to different surfaces.

The object of this invention, therefore, is to provide a highlyflexible, light weight, easily conformable insulation material, theconductance of which can be changed at will by inflation, in so doingsignificantly altering only its thickness dimension, and which can becarried and stored with littlebulk in its deflated state.

SUMMARY OF THE INVENTION The present invention is characterized by theprovision of thermal insulating material formed of sheets of non-porousflexible material hermetically sealed together to define an inflatablevolume divided into a two-dimensional array of compartments joined bygas In a featured embodiment of the invention, the individualcompartments are formed by bonds between the sheets of polymericmaterial at the intersections of lines defining the two-dimensionalarray. Utilization of materials that can be bonded together by any ofmany well-known techniques to form the compartment array greatlysimplifies the construction of thermal insulation according to theinvention.

According to another feature of the invention, at least one of theflexible material sheets possesses hexagonally arranged preformedblisters that define the compartments of the inflatable volume. Becauseof the preformed blisters, inflation of the compartments formed therebyintroduces no distortion in the overall shape of the material therebyfacilitating its use for items such as wearing apparel wherein aconstant uniform overall size is desired. The hexagonal arrangement ofcompartments enhances comfortableness by allowing uniform flexing of thematerial in any direction.

In another featured embodiment, the insulation material of the presentinvention is attached as a lining to an article of wearing apparel. Thelining flexes easily so as to readily conform to the anatomy of thewearer even during movement. Preferably the individual compartments ofthe array are relatively small with a maxi mum cross section of lessthan one square inch so as to provide the flexibility desiredfor anarticle of clothing. Also the individual compartments preferably have amaximum inflated thickness of less than one inch to further enhanceflexibility.

For applications requiring additional thermal insulation capability,another embodiment of the invention provides a third sheet of flexiblesheet material hermetically sealed over the inflatable volume formed bythe other sheets and providing an auxiliary volume that can be inflatedor deflated independently with a separate valve mechanism. When thedegree of insulation provided by inflation of the primary volume isinadequate,

.the auxiliary volume also can be inflated to further improve theinsulation properties of the material.

DESCRIPTION OF THE DRAWINGS These and other objects and features of theinvention will become more apparent upon a perusal of the followingdescription taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic illustration of an article of wear ing apparelaccording to the present invention;

FIG. 2 is a cross-sectional view taken along lines 2-2 in FIG. 1;

FIG. 3 is a more detailed plan view of a portion of the thermalinsulation material shown in FIGS. 1 and 2;

FIG. 4 is a cross sectional view taken along lines 44 FIG. 5 is a crosssectional view taken along lines 55 of FIG. 3 with the insulationmaterial inflated;

FIG. 6 is a partial perspective view of other compartmented array foruse in the insulation material of the present invention; and

FIG. 7 is a partial cross sectional view illustrating another insulatingmaterial embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2there is shown a coat 1 I having, in the conventional manner, an outercovering 12 and a lining 13. The materials composing the outer covering12 and the lining 13 are selected to provide desirable characteristicsof appearance, wear resistance, comfort, etc. Also, the outer covering12 can be opacified or coated reflectively to reduce heat conductancethrough radiation. Sandwiched between the outer layer 12 and the lining13 is an inflatable intermediate lining 14 described in detail below. Aconventional valve assembly 15 is associated with the intermediatelining 14 and permits inflation and deflation thereof. The valveassembly 15 is retained within a pocket 16 positioned so as to renderthe valve accessible to the mouth of a person wearing the coat 11. Thispermits a wearer to inflate the lining 14 by blowing into the valve 15.

FIGS. 3-5 show more detailed views of a portion of the thermalinsulation material 14 illustrated in FIGS. 1 and 2. The material 14 isformed by a first sheet 21 of non-porous, flexible material sealed alongouter edges 22 to a second sheet 23 of non-porous, flexible material soas to form a hermetically sealed inflatable volume 24. Preferably, thesheet materials 21 and 23 are formed of a suitable polymeric material orcoated fabric that possesses good strength and tear characteristics andremains non-rigid at sub-zero temperatures. Performed in the first sheet21 is an array of blisters separated by troughs 26 that divide thevolume 24 into compartments 27. The blisters 25 can be preformed by anysuitable technique such as heat forming, molding, etc. At hexagonallydistributed positions 28 the troughs 26 are bonded to adjacent portionsof the second sheet 23 so as to limit the degree of separation possiblebetween the sheets 21 and 23. Both the sealed edges 22 and the bonds 28can be created by a variety of well known methods including thermal heatsealing, impulse sealing, dielectric sealing, and ultrasonic welding aswell as by the use of coatings and adhesives.

The preformed blisters 25 permit inflation of the compartments 27without any stretching of the sheets 21 and 23 while the bonds 28 retaina minimum separation therebetween. Accordingly, the length d of thenon-inflated material section shown in FIG. 4 is the same as the lenghtD of the same section shown in FIG. 5 after inflation. This is animportant feature of the invention in that it insures that theperipheral dimensions of the material 14 will remain uniform. Because ofthis feature, the insulation liner will conform dimensionally with theouter covering 12 and provide a good fit in either the inflated ornon-inflated conditions. In this arrangement it is evident that the flatsurface 23 of FIGS. 3-5 can be the same as the inner lining 13 of FIG.2.

Another important feature of the invention is the division of theinflatable volume 27 into a twodimensional array of compartments 27. Thetroughs 26 define a plurality of intersecting lines along which thearray 14 can be easily flexed. Thus, the twodimensional array providedthe material 14 with flexibility in all directions adding substantiallyto the degree of comfort it provides to a wearer when used as an articleof clothing. Although other array patterns can be employed, thehexagonal pattern is preferred in that it provides the most uniformflexing ability in all directions. The ability of the material to flexcan be enhanced by reducing the size and increasing the density of thecompartments within the array. For the degree of flexibility desired forclothing, it is preferably that the maximum cross-sectional area of theindividual compartments as illustrated in FIG. 3 be no greater than onesquare inch.

The thickness of the material 14 is determined by the geometry orinflated height of the blisters 25 for a fixed pattern density. Thus,the pattern density or blister height can be varied as needed in a givenapplication to enhance or diminish flexibility, ventiliation,insulation, or bulkiness in local areas. Again however, for the use ofthe material in a clothing application it is preferred that the heightof the blisters be limited to less than 1 inch. Though the insulatingproperty tends to increase with greater blister height, for blisterheights greater than one inch the insulation effectiveness of the airfilled compartments is reduced by convection effects, overallflexibility is reduced and bulkiness is increased. For applicationswhere additional warmth is required, and so that the insulation can bevaried in increments, it is preferable to use two layers of material orto use a material provided with a multiple inflatable compartments asillustrated in FIG. 8 and described in greater detail below.

FIG. 6 shows in perspective another insulation material embodiment ofthe invention. The material 31 is formed by a first flat sheet 32 and asecond flat sheet 33, both formed ofa suitable non-porous flexiblematerial. The sheets 32 and 33 are hermetically sealed along their edges34 to form an inflatable internal volume therebetween. Bonds are alsocreated between the first and second sheets 32 and 33 at a plurality ofpoints 35 distributed in a hexagonal array. Because of the bonds 35, thematerial 3] assumes the quilted appearance shown in FIG. 7 afterinflation and provides the same selective degree of thermal insulationprovided by the embodiment shown in FIGS. 3-6. Although not quite asuniformly flexible or resistant to changes in peripheral dimensions asembodiment 14, the absence of preformed blisters simplifies constructionof the material 31.

Another insulation material embodiment 41 is schematically illustratedin FIG. 7. The material 41 includes first and second sheets 42 and 43,respectively, of nonporous flexible materials arranged identically tothe sheets 21 and 23 shown in FIGS. 3-5. However, in embodiment 41 athird sheet 44 of non-porous flexible material is hermetically sealed tothe sheet 43 providing an auxiliary volume 45 overlaying and coextensivewith a volume 46 defined by the first sheet 42. Each of the sheets 42and 44 includes preformed blisters 47 separated by troughs 48 thatdefine compartments as in the embodiment 14 shown in FIG. 3. Bonds 49are made between the flat second sheet 43 and directly adjacent throughportions of both the first and third sheets 42 and 44. During use ofembodiment 41, the volume 46 can be inflated through a suitable valve 51when increased insulation is desired and an even greater degree ofinsulation can be obtained by subsequently inflating the volume 45through an auxiliary valve 52.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. For example, althoughwearing apparel is a preferred application for the present thermalinsulation material, it will be obvious that the material can be usedalso for other articles such as sleeping bags, tents, blankets, etc.Also, in certain applications, the provision within the material ofisolated regions that would permit zonal inflation would provide greaterversatility,

particularly when used as an article of wearing apparel. in addition,the ability of the material to breathe can be easily established byproviding small openings through all sheets within the confines of thebonds 28, 35 or 49. it is to be understood, therefore, that theinvention can be practiced otherwise than as specifically described.

What is claimed is:

1. Thermal insulation comprising:

a first sheet of non-porous flexible material;

a second sheet of non-porous flexible material hermetically sealed tosaid first sheet around a peripheral edge so as to define therebetweenand inflatable volume, opposite portions of said peripheral edge beingjoined by portions of said first sheet having a length in the directionof separation of said opposite portions substantially greater than themaximum normal separation possible between said opposite portions inthat direction;

divider means dividing said inflatable volume into a two-dimensionalarray of compartments joined by gas communication passages; and

valve means for introducing gas into said inflatable volume.

2. Thermal insulation according to claim 1 wherein said divider meanscomprise direct bonds formed between said first and second sheets offlexible material.

3. Thermal insulation according to claim 1 wherein the boundariesbetween said compartments of said twodimensional array define aplurality of intersecting lines along which said array can be easilyflexed.

4. Thermal insulation according to claim 3 wherein the divider meanscomprise bonds formed between said first and second sheets of flexiblematerial at said intersections of said lines.

5. Thermal insulation according to claim 1 wherein discrete area of saidfirst sheet of flexible sheet material are preformed blisters thatdefine said compartments.

6. Thermal insulation according to claim 5 wherein the boundariesbetween said compartments of said twodimensional array define aplurality of intersecting lines along which said array can be easilyflexed.

7. Thermal insulation according to claim 6 wherein said divider meanscomprise bonds formed between said first and second sheets of flexiblematerial at the intersections of said lines.

8. Thermal insulation according to claim 5 including a third sheet ofnon-porous flexible sheet material providing a hermetically sealedauxiliary volume overlaying and coextensive with said inflatable volume,and auxiliary valve means for introducing gas into said auxiliaryvolume.

9. Thermal insulation according to claim 8 wherein discrete areas ofsaid third sheet of flexibe material are preformed blisters aligned withsaid blisters in said first sheet of flexible sheet material.

10. Thermal insulation according to claim 1 wherein said inflatablevolume has a configuration corresponding to a portion of the humananatomy.

11. Thermal insulation according to claim 10 including an article ofwearing apparel to which said first and second flexible sheets areattached as a lining.

12. Thermal insulation according to claim 11 wherein the boundariesbetween said compartments of said two-dimensional array define aplurality of intersecting lines along which said array can be easilyflexed.

13. Thermal insulation according to claim 12 wherein said divider meanscomprise bonds formed between said first and second sheets of flexiblematerial at the intersections of said lines.

14. Thermal insulation according to claim 11 wherein discrete areas ofsaid first sheet of flexible sheet material are preformed blisters thatdefine said compartments.

15. Thermal insulation according to claim 14 wherein the boundariesbetween said compartments of said two-dimensional array define aplurality of intersecting lines along which said array can be easilyflexed.

16. Thermal insulation according to claim 11 wherein said compartmentshave a maximum inflated thickness of less than one inch.

17. Thermal insulation according to claim 16 wherein said compartmentshave a maximum crosssection 'of less than one square inch.

18. Thermal insulation according to claim 1 wherein said two-dimensionalarray is a hexagonal array.

19. Thermal insulation comprising:

a first sheet of non-porous flexible material;

a second sheet of non-porous flexible material hermetically sealed tosaid first sheet around a peripheral edge so as to define therebetweenan inflatable volume;

bonding means directly bonding said first sheet and said second sheettogether at spaced points within said peripheral edge so as to dividesaid inflatable volume into a two-dimensional array of compartmentsjoined by gas communication passages between said compartments andwherein said first and second sheets are of such area as to permitsubstantial increase in the volume of said compartments in response toinflation thereof without distortion of said peripheral edge; and

valve means for introducing gas into said inflatable volume.

20. Thermal insulation according to claim 19 wherein the boundariesbetween said compartments of said two-dimensional array define aplurality of intersecting lines along which said array can be easilyflexed.

21. Thermal insulation according to claim 19 wherein discrete areas ofsaid first sheet of flexible sheet material are preformed blisters thatdefine said compartments.

22. Thermal insulation according to claim 19 wherein saidtwo-dimensional array is a hexagonal array.

1. Thermal insulation comprising: a first sheet of non-porous flexiblematerial; a second sheet of non-porous flexible material hermeticallysealed to said first sheet around a peripheral edge so as to definetherebetween and inflatable volume, opposite portions of said peripheraledge being joined by portions of said first sheet having a length in thedirection of separation of said opposite portions substantially greaterthan the maximum normal separation possible between said oppositeportions in that direction; divider means dividing said inflatablevolume into a twodimensional array of compartments joined by gascommunication passages; and valve means for introducing gas into saidinflatable volume.
 2. Thermal insulation according to claim 1 whereinsaid divider means comprise direct bonds formed between said first andseconD sheets of flexible material.
 3. Thermal insulation according toclaim 1 wherein the boundaries between said compartments of saidtwo-dimensional array define a plurality of intersecting lines alongwhich said array can be easily flexed.
 4. Thermal insulation accordingto claim 3 wherein the divider means comprise bonds formed between saidfirst and second sheets of flexible material at said intersections ofsaid lines.
 5. Thermal insulation according to claim 1 wherein discretearea of said first sheet of flexible sheet material are preformedblisters that define said compartments.
 6. Thermal insulation accordingto claim 5 wherein the boundaries between said compartments of saidtwo-dimensional array define a plurality of intersecting lines alongwhich said array can be easily flexed.
 7. Thermal insulation accordingto claim 6 wherein said divider means comprise bonds formed between saidfirst and second sheets of flexible material at the intersections ofsaid lines.
 8. Thermal insulation according to claim 5 including a thirdsheet of non-porous flexible sheet material providing a hermeticallysealed auxiliary volume overlaying and coextensive with said inflatablevolume, and auxiliary valve means for introducing gas into saidauxiliary volume.
 9. Thermal insulation according to claim 8 whereindiscrete areas of said third sheet of flexibe material are preformedblisters aligned with said blisters in said first sheet of flexiblesheet material.
 10. Thermal insulation according to claim 1 wherein saidinflatable volume has a configuration corresponding to a portion of thehuman anatomy.
 11. Thermal insulation according to claim 10 including anarticle of wearing apparel to which said first and second flexiblesheets are attached as a lining.
 12. Thermal insulation according toclaim 11 wherein the boundaries between said compartments of saidtwo-dimensional array define a plurality of intersecting lines alongwhich said array can be easily flexed.
 13. Thermal insulation accordingto claim 12 wherein said divider means comprise bonds formed betweensaid first and second sheets of flexible material at the intersectionsof said lines.
 14. Thermal insulation according to claim 11 whereindiscrete areas of said first sheet of flexible sheet material arepreformed blisters that define said compartments.
 15. Thermal insulationaccording to claim 14 wherein the boundaries between said compartmentsof said two-dimensional array define a plurality of intersecting linesalong which said array can be easily flexed.
 16. Thermal insulationaccording to claim 11 wherein said compartments have a maximum inflatedthickness of less than one inch.
 17. Thermal insulation according toclaim 16 wherein said compartments have a maximum cross-section of lessthan one square inch.
 18. Thermal insulation according to claim 1wherein said two-dimensional array is a hexagonal array.
 19. Thermalinsulation comprising: a first sheet of non-porous flexible material; asecond sheet of non-porous flexible material hermetically sealed to saidfirst sheet around a peripheral edge so as to define therebetween aninflatable volume; bonding means directly bonding said first sheet andsaid second sheet together at spaced points within said peripheral edgeso as to divide said inflatable volume into a two-dimensional array ofcompartments joined by gas communication passages between saidcompartments and wherein said first and second sheets are of such areaas to permit substantial increase in the volume of said compartments inresponse to inflation thereof without distortion of said peripheraledge; and valve means for introducing gas into said inflatable volume.20. Thermal insulation according to claim 19 wherein the boundariesbetween said compartments of said two-dimensional array define aplurality of intersecting lines along which said array can be easilyflexed.
 21. Thermal insulation according to claim 19 wherein discreteareaS of said first sheet of flexible sheet material are preformedblisters that define said compartments.
 22. Thermal insulation accordingto claim 19 wherein said two-dimensional array is a hexagonal array.